[thedanbob]

As I understand it, Apple slowed down certain models to deal with the problem of batteries losing capacity over time. Which actually could give those phones a longer usable life (slower is better than shutting off completely). The problem was they didn't tell people they were doing it.

[mrguyorama]

Also usable here should be in pretty big quotes. The phone didn't die and turn off, but it didn't get much done either. It could possibly still make phone calls

[valuearb]

No, the phone was still usable, just slower.

If Apple didn’t throttle, the phone would restart every time it’s power requirements outstripped the batteries declining capacity.

I think it’s pretty clear which use case is better.